The prior art includes a number of regulated high voltage power supplies that employ, among other things, dc--dc converter techniques, including transformer coupling between the low voltage and high voltage sections. The prior art that includes regulation on the low voltage side of a dc--dc converter presents problems with respect to isolation of the regulated sensed high voltage from the low voltage side of the power supply. The prior art that includes regulation entirely on the high voltage side has generally required substantial dissipation of power in the circuit elements employed for regulation, such as with series or shunt active elements.